Orthoester stabilized polyvinyl-chloride resins



United States Patent US. Cl. 260-45.8 2 Claims ABSTRACT OF THEDISCLOSURE Polyvinyl chloride resin is thermally stabilized by theaddition of the orthoester CH C(OCHzCHOH A polyhydric alcohol R(OH)where R is an organic radical and x has a value of from 1-6 may also beadded in a concentration of 1% to to further enhance the thermalstability.

The present application is a division of my application 612,066 filedDec. 12, 1966, now abandoned, which in turn is a continuation-in-part ofmy earlier filed applications, Ser. No. 403,353, filed Oct. 12, 1964 nowabandoned and 499,093, filed Oct. 20, 1965 now abandoned.

The present invention relates to the stabilization of resins, and morespecifically to a novel stabilization agent for stabilizing vinylchloride polymers and copolymers against the degradation effects ofelevated temperatures.

It is well know that vinyl chloride containing resins degrade atelevated temperatures. When vinyl chloride polymers and copolymers aresubjected to molding temperatures in excess of about 150 C. they tend todiscolor. Serious discoloration occurs even in the relatively shortperiod of time required for a molding operation.

To date, numerous stabilizers have been suggested for use in vinylchloride type resins. The most satisfactory of these stabilizerscomprise tin, lead and cadium containing compounds. These compounds,while performing satisfacton'ly where toxicity is not a problem, cannotbe used where the treated polymer is to come into contact withfoodstuffs and the like.

As of present, a highly effective polyvinyl chloride stabilizer whichdoes not possess toxic characteristics or propensities has not beendeveloped.

It is therefore an object of the present invention to provide a novelclass of polyvinyl chloride stabilizers.

It is another object to provide novel stabilizers for polyvinyl chloridecontaining resins which substantially enhance thermal stability of saidresins.

It is a further object to provide a class of polyvinyl chloridestabilizers which are non-toxic and may be used in resins which are usedin the packaging of foodstuff materials.

These and still further objects of the present invention will becomereadily apparent to one skilled in the art from the following detaileddescription and specific examples.

Broadly, my present invention contemplates as polyvinyl chloridestabilizers compounds containing the following orthoester grouping:

ice

wherein the indicated unsatisfied valences are occupied by hydrogen ororganic radicals. It is also contemplated that these orthoesters may beeffectively combined with polyhydric alcohols to give a superior degreeof stabilization.

More specifically, I have found that if from about 1% to about 10% byweight of a compound containing an orthoester grouping is admixed withpolyvinyl chloride, the orthoester compound will stabilize the polyvinylchloride towards heat induced degradation. Furthermore, thisstabilization effect may be enhanced by the addition of polyhydricalcohols.

The orthoesters used in the practice of the present invention may bebroadly defined as those orthoesters which possess at least one of theabove defined orthoester groups, and which are compatible with thepolyvinyl chloride resins at the processing temperatures indicated. Bythe term compatible it is meant that the orthoester used shouldhomogenously blend with the polyvinyl chloride and should have arelatively low vapor pressure at processing temperatures so as not tocause excessive foaming of the resins at the processing temperaturesencountered.

Typical structures of suitable orthoesters which may be used in thepractice of my invention are.

0 R+OR2 0 s wherein R may represent hydrogen, alkyl, phenyl,phenylalkyl, alkylphenylalkyl, halophenyl, nitrophenyl and alkenyl, R RR may be alkyl, phenyl, phenyl-alkyl, alkylphenyl, and alkylphenyl-alkylwherein R R and R has the meaning given in (1) above; K, may bealkylene, phenylene, and alkylphenylene; and X represents oxygen andsulfur.

3 R R O wherein R and R have the meaning given in (1) above; and R maybe alkylene, alkylal-kylene, and alkenylalkoxyalkylalkylene.

wherein R has the meaning given above and R is alkylene. The reactionproducts of lower orthoesters such as tri ethyl orthoacetate andtriethylorthoformate with polyols such as glycerol, sorbitol, andmannitol yield complex esterified products.

Specific examples of orthoesters which may be used in the presentinvention along with a general description of how the orthoestercompound may be prepared are given in the following paragraphs. (Thenumeral designations will be used in the subsequent specific examplesand claims to identify these compounds.)

The following three methods may be used to prepare the followingorthoesters:

(A) Iminoester route, as set forth in Pinner, Ber., 16 356, 1644 (1883).

The appropriate nitriles are reacted with one equivalent of dry hydrogenchloride and one equivalent of alcohol to form an iminoesterhydrochloride which is then alcoholyzed with an excess of alcohol toform the orthoester. The reaction may be outlined as follows:

GXCBSS ROH RON ROH H01 RCOR' NHzCl RO(OR')a NH4C1 A dinitrile can beused as follows:

NCRCN 2R0H 21101 NHzCl NH2C1 H RO RiioR' (R'O)3ORO(ORI)3ZNH4C]Furthermore, diols may be used at either one or both steps of thesynthesis.

GX CBSS NH201 NHzCI ZRCN HOROH 2HC1 R'COR'OOR (B) Exchange reaction asdescribed by Mkhitaryan, V. J. Gen. Chem. (USSR) 8 1361 (1938).

The alkoxy groups of a readily available orthoester such as triethylorthoacetate or formate are displaced by a higher boiling alcohol orpolyol as follows:

Furthermore, the reaction may be carried out in two steps with twodiflferent alcohols or polyols including polyols ranging from diols tohexols. Typically the reaction may be illustrated for a diol as follows:

When more complex polyols including triols through hexols are used, manycomplex polymeric products are possible. However, these reactionproducts are formed by continuing the reaction until the requiredamounts of lower alcohol has been removed. That is the exchange reactionis continued until the calculated amount of lower alcohol is displacedby the higher alcohols.

(C) Alcoholysis of triholomethyl groups as set forth by Sah, P. and Ma,S.T., J. Am. Che. Soc. 54 2964 The appropriately substitutedtrichloromethyl compound is treated with a metal alkoxide.

4 This compound is conveniently prepared by route A or B.

CH3O-OCH2 OCCHS This compound is prepared by route A or B.

(III) C2115 C2115 5 8 oH3-bo-0H2o5OoH20- b-cH This compound is preparedby route A or B.

(IV) CH2 CH2 OH;CI i \CHZ GHQ-C CH2 0 CH3 0 O CHs C O( JHCH2--CH2O CCH3This compound is prepared by route A or B.

(V) CHg-CH; CH2--CH2 6 5 5 6 CH3 COCHzCHrO-CHzCHzO O CH This compound isprepared by route A or B.

(VI) CH3CHOHZ CHz-CHCH;

o 0 CH 0 CH OO( JH2CHz-O CC1Ia This compound is prepared by route A orD.

(V O--CH:

OH G0CH C-CH;CH

OC z

This compound is prepared by route A.

(VIII) CHzO CHzCH=CH2 am o-o OHrHOH2O-COH 11.33 as. 11.8; 311;

H5C2CCH2O OH2CH=CH2 Oz Hs CHzO CHzCH=CHg This compound is prepared byroute B.

(IX) (CH CH CH O9 CtCH C(-OCH CH CH 3 t This compound is prepared byroute A or B.

CH3GTOCHfl 'C-- -CH2 3 This compound is prepared by route B. (XI) CH3\/CH3 CH3\ /0H;

0 C Cz CHz Cz \CH2 CH3 3) (I) OHa CO CH2+ CH20 CCH3 This compound isprepared by routes A and B. wherein n has a value greater than 1.

This compound is prepared by route B.

(XII) CH C(OC H This compound is prepared by route A.

(XIII (CH O) CCH CH SCH CH C-OCH 3 This compound is prepared by route A.

(XIV) (C H O CCH CH SCH CHC OC H 3 This compound is prepared by route A.

(XV) (CH O CCH CH OCH CH C (OCH 3 This compound is prepared by route A.(XVI) CH (CH C(OCH This compound is prepared by route A.

I Ol{C(OCHa)a (XVII) This compound is prepared by route C. (XVIII)CH3(l3(OCH2(CH2)sCH3)z This compound is prepared by route A. 3 )a 2)43)3 This compound is prepared by route A.

This compound is prepared by route A.

(XXI) O O2H5 (321- 0 CZHE CH -C-O CHz-CO-CCH O O 2H5 C 2H5 CH2OCH2CH=CH2This compound is prepared by route B.

(XXII) (HI -0H CH2--CH2 5 6 om 0oomomo com This compound is prepared byroute B.

(XXIII) (32H:

H( 3O 02H.

This compound may be prepared by routes A, B, or C.

CH3 CZOCH2CH2O CZCHK This compound may be prepared by route B.

This compound was prepared by route B.

This compound was prepared by route B.

(XXVII) Poly(glyceryl orthoformate) This compound was prepared by way ofroute B using one mole of triethyl orthoacetate and one molev ofglycerol.

(XXVIII) Poly(sorbityl orthoacetate) This compound was prepared by routeB from 2 moles of triethyl orthoacetate and one mole of sorbitol.

(XXIX) Poly (mannityl orthoacetate) (XXV) (XXVI) where R is an organicradical and x has a value of from 1 to 6. Preferably these alcohols havea boiling point in excess of about 175 C.

In the above formula R may be alkyl, alkylphenyl, phenylalkyl, alkylene,phenylene, polyalkoxyalkylene and and trivalent counterparts thereof.Typical polyhydric alcohols useful in the practice of the presentinvention are o/m,p-xylene, a, a-diol, trimethylolpropane monopropylether, trimethylolpropane monoallyl ether, propylene glycol, diethyleneglycol, dimethyloctadiynediol, pentaerythritol, trimethylolpropane,neopentylglycol, :benzylalcohol, cetyl alcohol and dipentaerythritol.

Polyvinyl chlorides which are treated in accordance with the practice ofmy present invention are those vinyl chloride polymers and vinylchloride copolymers having a npmber average molecular weight from about10,000 to about 150,000 and a weight average molcular weight of fromabout 20,000 to 1,000,000. These vinyl chloride polymers and copolymersare well known to those skilled in the art and comprise vinyl chloridehomopolymers as well as vinyl chloride copolymers which are prepared bycopolymerizing vinyl chloride with a copolymerizable monomer such asunsaturated esters which include vinyl acetate, vinyl 'formate, vinylbenzoate, vinyl stearate, vinyl oleate, as well as diethyl maleate anddiethyl formate. Copolymers may also be prepared by copolymerizing vinylchloride with an acrylic ester such as methyl-, ethyl-, butylandoctylacrylate. It is also contemplated that the vinyl chloridecopolymers may be prepared by polymerizing vinyl chloride withvinylidene chloride. The above mentioned copolymers may contain from Oto 20, and even 400 by weight of copolymerizable monomer.

The stabilization agents, namely the orthosters contemplated herein, areincorporated with the vinyl chloride polymer and copolymers by anyconventional means. The

blending may be conveniently carried out first preparing a slurry offinely divided polymer in a solvent for the orthoester such as methanol,acetone, ethyl ether. The solution is then separated from the slurry andthe polymer particles are dried. This results in polymer particles whichare throughly coated with the othoesters set forth herein. It is alsocontemplated that the blending may be achieved by milling the polymer atthe softening temperatures therefor until an intimate blend of thestabilization agent with the polymer is achieved. Milling is generallyconducted at conventional temperatures of to 200 C. for a period of timesufficient to obtain thorough blending of the stabilization agent withthe polymer.

The stabilized vinyl chloride polymers and copolymers contemplatedherein may be used in the formation of rigid polyvinyl chloride moldedarticles. These rigid molded pieces are formed in extrusion andinjection molding devices which are well known to those skilled in theart and which operate in the neighborhood of 150 to 200 C. Thestabilization agents contemplated herein eifectively stabilize the vinylchloride poly-mer and copolymer during the molding process and make itpossible to produce rigid moldings having a low degree of color changeand good clarity.

It is also contemplated that the polyvinyl chloride resins stabilized bythe present stabilizers may be admixed with various plasticizers such ashigh boiling esters including the alkyl phthalates, phosphates,adipates, sebacates, azolates, and various polymeric type estersplasticizers. Also the present composition may contain other additivessuch as 11, Zn, Mg, Sn and Ca salts of carboxylic acids, and phosphateesters. Furthermore, the resins may be included in plastisol typepreparations which are fabricated by dipping and deposit type moldingtechniques.

Having described the basic aspects of my present invention the followingspecific examples are given to illustrate embodiments thereof.

7 EXAMPLE 1 -In the examples tabulated below 9.5 g. portions of powderedVygen 120, a high molecular weight polyvinyl chloride resin, wasslurried in solutions which comprised 20 ml. of methanol and 0.5 g. ofthe various stabilizer compgundsi l1sted belofiv. The resultantslurriesfwere zgap- EXAMPLE H orate to ryness wit constant agitation atrorn to 60 C. and under 60 mm. Hg pressure. 3.5 g. of the polythefollOWlng runs pdrtlclllflt6 polyflinyl chlollde vinyl chloride mixtureswere then pressed into plaques haVlIlg a number average K101091111lrWelght of about whi h me r d 1" X 3" d 5 il i thi kn n a 38,000 was dryblended with var1ous amounts of orthopress heated to 200 C. and exerting10,000 p.s.i. for the s s an r polyhydnc alcohol. These samples weretimes listed in the table below. The color of the resultant then placedin the mixing chamber of a Brabender Plas- 1 plaques were measured bycomparison with the standard t graph at 190 C. and open to the air. Aroller speed Gardner color scale ((lhcolorless to 5.0=dark amber). 0f 60-P- Was used to knead the P y formulations- The less color developed inthe plaque the more eifective Th9 Brabendef Plastograph Continuouslyrecords the i th t bili r, torque required to knead the mass. From thetorque values one can determine:

(a) The time required for the powder mixture to fuse 1 into a workableplastic mass (flux time) Gardner Color Index at (b) The force requiredto work the plastic mass (aver- Various Time (minutes) age torque value)Stabilizer 2 5 10 15 (c) The onset of crosslinking (decomposition time).

The actual temperature of the plastic mass was also con- 2.0 2.25 2.52.5 tinuously measured. Small samples of the polymers were g alsoremoved periodically from the mixing chamber and 15 15 15 15 their colorcompared to those of the standard Gardner scale.

TABLE II Decomposition Concentime tration Flux after Polymer Color(Gardner Scale 0=Co1orless; 15=Brown Stabilizer (numerals referorthoester (parts per time, flux, Torque, temp., Run describedpreviously) hundred) min. min. KG degrees 21mins. mins. 10mins. 15mins.20 mms. 5.0 2.0 20.0 1.25 199-204 1.5 1.8 1.5 1.5 1.5 1.5 20.0 1.25193-199 0.2 0.2 0.5 1.0 1.2,15 2.0 17.0 1.3 195-208 1.0 1.0 1.0 1.5 1. 522.0 1.1 190-198 1. 5 1. 5 1. 5 1. 5 z 1. 5 2. 0 3. 5 10-13. 5 1. 9-1. 5190-210 1. 5 15 2. 0 3. 5 3.0-8. 0 1. 9-1. 7 190-210 1. 5 15 2. g 2. 53. 5 1. 9-1. 7 190-198 15 5.

0 1. 5 34. 0 1. 4-1.2 190-197 1.0 2.0 2.0 2.0 4 2.0 2. 2. 0 1. 0 3. 0 1.9-2. 2 180-194 5. 0 2. 0 14. 5 1. 3-1. 4 190-203 1. 5 g: g l 2. 0 12. 51.4 190-200 1. 0 1. 0 1. 0 3-8 2. 5 17. 0 1. 8-2. 0 190-202 1. 0 1. 0 1.0 1. 0 5.0

}- 3.0 25.0 1.3-1.4 194-207 1.5 1.5 2.0 2 0 9 2. 0,2 0 2.0 5. 0 2. 519 1. 4 194-207 2. 0 3-8 2.0 27 1.1 190-198 1.5 38 2. 0 31 1. 1190-190 1. 0 5. 0 2. 0 11. 5 1. 1-1. 4 190-199 2. 0 3-8 2. 5 15. 5 1.1-1.4 188-190 1. 0 5. 0 2. 0 7. 5 1. 4 190-198 1. 0 5. 0 9. 0 8. 5 1. 4-192 1 1. 0 2. 5. 0 2. 0 12. 0 1. 4-1. 0 190-214 1. 5 1. 5. 0 2. 0 8.5 1. 4 189-190 1. 0 1. 5. 0 1. 0 8. 5 1. 2-1. 8 180-197 2. 2 2. 5. 0 1.0 B 12-21 1.6-1.8 181-210 2. 2 3. 0 3-3 1.0 22.0 1.3-1.8 178-200 0.5 0.5 0.5 0.5 0.5 v 5.0 20 CH=CHZC' (CH2H)2 1 0 25.5 1.1-1.8 180200 0.7 0.70.7 0.7 0.7

OH OCH CH -oH l 1. 0 11 1. 4-1.8 172-188 0 0 0. 5 5. o 1. 0 11 1. 2-1. 8182-199 2. 2 2. 8 2. 0 5. 0 1. 5 17 1. 3-1. 8 185-203 2. 0 2. 3 2. 5 3.0 1.0 21 1. 2-1.8 -200 0.8 1.2 2.5 2.5 7.0 5. 0 0. 7 15 1. 1-1. 8170-200 2. 2 2. 2 2. 2 2. 5 Z 8 2. 5 10 1.1-1.8 100-200 1.2 1. 2 1. 2 1.8 g. g 1. 0 a 13 1. 2-1. 8 182-198 1. 5 1. 5 15 1:8 3.0 21 1. 2-1. 3180-190 0. 2 0. 5 1.0 2.0 2.0

8 Example 1 and 2 containing the orthoesters contemplated herein areeffectively stabilized. Example 3 which contained the well knownstabilizer dibutyltin dilaurate rapidly discolored under the sameconditions as did Example 4 which contained no stabilizer.

TABLE II-Co11tinued Decomposition Coneentime tration Flux after PolymerColor (Gardner Scale =Colorless; 15=Brown) Stabilizer (numerals referorthoester (parts per time, flux, Torque, temp, Run describedpreviously) hundred) :mm. mm. KG degrees 2 mins. 4 mins. mins. mms.mlllS.

8:8 1.0 22. 0 1.8-1.8 178-200 0. 5 0. 5 0. 5 0. 5 0. 5 8:8 1.0 18. 5180-199 0. 5 0.8 0.8 0.8 8: 8 1. 0 13. 0 182-200 0. 3 0. 5 0. 5 2. 0 20 1. 5 I 8. 0 180-195 0. 3 8:8 1.0 9. 5 180-195 0.3 5.0 2.0 1 5 1.2-1.4182-197 2.0 3.0 4. 0 2. 0 17 1. 1-1. 3 190-198 2. 0 3. 0 4. 0 2. 0 101.2-1.4 178-202 2. 5 3. 0 2. 0 2. 0 7. 5 1.2-1.4 185-195 2. 0 2. 5 1. 02. 0 3. 0 1. 2-1. 4 188-192 2. 5 2. 8 3. 0 4. 5 1. 85 201-212 8 15 10. 03. 0 9. 0 1. 8 190-208 2. 5 3. 0 10. 0 3. 0 9. 5 1.3-1.4 184-193 5. 0 5.0 5. 0 2. 0 14. 0 1. 3-1. 4 190-203 1. 8 1. 8 4. 0 3. 0 9. 0 1. 1-1. 4194-203 1. 8 1. 8 3. 0 2. 5 5. 5 1. 4 193-201 1. 8 1. 8 2. 0 2. 5 4.5 1. 3-1. 4 194-200 2. 5 3. 0 1. 0 4. 0 2. 0 1. 3-1. 5 180-188 1. 0 {8}2. 0 15.5 1 3-1.4 190-205 0. 5 8:8 2. 5 11.0 1.3-1 4 190-200 0. 5 8:8 3.5 4. 5 1.1-1. 5 185-198 0 5. 0 2. 0 15 1. 1-1. 3 190-199 1. 5 8:8 2.0 191.1-1.4 188-205 1.0 5. 0 o 5. 5-5. 0 1. 75-2. 1 174-192 7. 0 5. 0 0 5.5-7. 5 1. 5-1. 9 193-208 5 5. 0 0 9-10 2. 0-2. 4 194-200 2. 0 5. 0 09-10 1. 8-2. 1 180-218 5. 0 5. 0 2. 0 i 0 14 1. 8-2.4 190-212 2 0 2. 5 59s 2. 0 0 5. 5 1.8-2.4 192-205 2. 0 5. 5 0.3 "X11 59 Cetyl 51551151. 2.0 0 15. 5 1. 4-2. 4 190-210 2. 0 2. 0 2. 0 3. 0

stearlilefieii g XX 70 C tyl a hoL 2. 0 0 7. 5 1. 7-2. 4 190-214 7. 5 7.5

71 e y 300 o {Steam acid 5 0 5. 5 1. 9 2.1 192 210 15 1 After 25 min.After 25 min., 3.5 after min. 9 Biacg, after 23.5 min. Z filitgriuzii Be no 4 At 30 min. Black at 7.5 min. 6 At 25 min. Blaek.

I l i References Cited A i g .g g t gg i UNITED STATES PATENTS composi1on compnsrng p Vll'l orthoester of formula 50 2,789,101 4/1957 W1ls0n26045.85 XR DONALD E. CZAIA, Primary Examiner CHPC (O OH2 C CH2)3 M. I.WELSH, Assistant Examiner 2. The composition of claim 1 which containsfrom about 1 to about 10% by fweight o1f7.n lcoho 1having CL a boilingpoint in excess 0 a out an avmg the formula R(OH) wherein R is anorganic radical 260 18,3051313445145 and x has a value of from 1 to 6.

